UPDATE:Wikipedia will also blackout its pages on Wednesday. See more details here, and below.

A vote on the controversial Stop Online Piracy Act (SOPA) has been delayed indefinitely, but the fight against Internet censorship continues: Reddit.com will go forward with its site-wide blackout on Wednesday, January 18, to protest the Senate’s Protect IP Act (PIPA), Digital Trends has confirmed. PIPA, a similar bill to SOPA, is scheduled to go up for a vote before the Senate on January 24.

“Protect IP Bill is still scheduled for a vote. Senator Reid said on Sunday that they’re still going forward with it, so [the Reddit blackout is still on],” said Erik Martin, Reddit’s general manager, in a phone interview with Digital Trends on Monday morning.

While SOPA has received the brunt of the backlash, PIPA contains similar provisions, which critics say could usher in an unprecedented level of government-enforced censorship online, harm the underlying infrastructure of the Internet, and hamper online innovation by stifling investment in Internet startups due to a more risky investment environment.

In the face of constituent outrage, Sen. Patrick Leahy (D-VT), co-author of PIPA, said in a statement on Thursday that he would be willing to remove the portion of the bill that would empower Internet service providers (ISPs) to block access to foreign websites that have been accused to distributing copyrighted material illegally. Despite the possible removal of this highly contentious provision, the Electronic Frontier Foundation’s Trevor Timm wrote on the EFF’s website today that “the fight is still far from over,” due to a number of other potentially “damaging” parts of the bill. These include the “vigilante” provision, which allows ISPs to block sites voluntarily, without recourse; and the anti-circumvention provision, which seeks to punish sites that give users information for how to access blocked sites.

In addition to Sen. Leahy’s admitted willingness to remove one of the most-criticized parts of PIPA, six Republican senators sent a letter to Senate Majority Leader Harry Reid, urging him to postpone a vote on the bill, reports ComputerWorld.

“We have increasingly heard from a large number of constituents and other stakeholders with vocal concerns about possible unintended consequences of the proposed legislation, including breaches in cybersecurity, damaging the integrity of the Internet, costly and burdensome litigation, and dilution of First Amendment rights,” the senators said in the letter. Signers of the letter include Senators Charles Grassley (R-IA), Orrin Hatch (R-UT), Jeff Sessions (R-AL), John Cornyn (R-TX) Mike Lee (R-UT), and Tom Coburn (R-OK).

Greater focus on PIPA follows an announcement from House Oversight Chairman Darrell Issa (R-CA), a vocal opponent of SOPA, who said that House Majority Leader Eric Cantor (R-VA) “assured” him that SOPA will not be brought up for a full House vote until consensus on the bill is achieved.

“While I remain concerned about Senate action on the Protect IP Act, I am confident that flawed legislation will not be taken up by this House,” Issa said in a statement, quoted by The Hill. “Majority Leader Cantor has assured me that we will continue to work to address outstanding concerns and work to build consensus prior to any anti-piracy legislation coming before the House for a vote.”

Sen. Cantor’s promise to shelve SOPA indefinitely — a major win for the opposition — follows a statement from President Obama’s chief technology officer, Aneesh Chopra, and National Security Staff cybersecurity coordinator Howard Schmidt, which said that the White House “will not support legislation that reduces freedom of expression, increases cybersecurity risk, or undermines the dynamic, innovative global Internet.” The statement is not an explicit declaration that President Obama would veto SOPA or PIPA, were they to make it to his desk, but the possibility of such a veto appears to have resonated on Capitol Hill.

In addition to Reddit, BoingBoing, Mojang, Destructoid, Anonymous, and the entire Cheezburger Network have announced blackouts planned for Wednesday. We are in the process of contacting each of these parties to confirm whether or not they still plan to follow through. Wikipedia, one of the first sites to propose a blackout protest, has not yet announced its plans. (SEE DETAILED UPDATES BELOW.)

UPDATE 2:Cheezburger Network CEO Ben Huh has confirmed with Digital Trends via Twitter that all of its sites, including I Can Haz Cheezburger, The Daily What, Know Your Meme, and others, will also be blacked out on Wednesday. Huh urges readers to call their Senators to voice their opposition to PIPA.

UPDATE 3: BoingBoing will also follow through with its blackout plans, according to a tweet by BoingBoing’s Xeni Jardin.

UPDATE 4: Wikipedia co-founder Jimmy Wales says that the ubiquitous online encyclopedia will go offline for 24 hours on Wednesday, according to Neal Mann, digital news editor at Sky News. The blackout will only apply to English-language articles, and will last from 12am ET, through 11:59pm, on Wednesday, Jan. 18.

UPDATE 5: Destructoid Editor-in-Chief Dale North has confirmed with Digital Trends that it too will follow through with its blackout plans. And an Anonymous spokesperson, Arturas Rosenbacher, the man behind @AnonDaily on Twitter, tells us that a number of popular Anonymous-affiliated Twitter feeds will also go dark on Wednesday. A number of other Anonymous-related Twitter feeds, including @AnonDaily, will remain live to report on the day’s various blackouts and the surrounding activities. We’ll have more details on Anonymous’ Jan. 18 plans, and how to follow the action online, tomorrow morning.